2. Four elements of air conditioning
1) Temperature : The dry-bulb temperature by cooling or heating room air.
2) Humidity : A comfortable humidity condition of room air is generally kept by the relative humidity of
air, and the room air is controlled into a given relative humidity condition.
3) The degree of purity : Remove dusts in the air, and keep smoke from exceeding the allowable degree of
concentration.
4) Air flow : To disperse properly the air regulated in temperature, humidity and the degree of purity
into indoor, make an appropriate air flow and keep uniformly the temperature/humidity
condition of room unit.
• Standard for feeling comfortable
3. Principle of refrigerating cycle
3.1 Principle of refrigerating : It is as follows.
1) Sprinkling with water in summer causes to cool surroundings.
• Because water absorbs the heat of surroundings with evaporating.
2) Gasifying a liquid (R-22) which is easier to evaporate than water makes cooler.
• Because water evaporates at 100°C under 1 atmosphere but freon gas (R-22) does a very low temperature of
-40°C
3) It is an Airconditioner that the principle is used for.
Classification Summer Winter
Temperature 21 ~ 28°C 20 ~24°C
Relative humidity 30 ~ 60% 30 ~ 60%
Air flow 0.2m/s or less 0.2m/s or less